1. Field of Invention
The present invention relates to a flexible land grid array connector. More particularly, the present invention relates to a flexible connector between a land grid array connector and a printed circuit board.
2. Description of Related Art
Integrated circuits are typically housed within a package, which is designed to protect the circuit from damage, provide adequate heat dissipation during operation, and provide electrical connection between the integrated circuits and the leads of a printed circuit board. Several conventional package types, such as land grid array (LGA), pin grid array (PGA), ball grid array (BGA) and column grid array (CGA), are designed to provide the above functions.
The current trend for connector design in the computer field is to provide both high-density and high-reliability connections between various major circuit devices of a computer. High reliability for such connections is essential due to potential end product failure. As both module size and distance from which solder connections are located to the center of the module (i.e., the distance from neutral point, hereafter DNP) continue to increase, even CGA solder connections can become unreliable, especially due to thermal fatigue. These same concerns about broken interconnections also apply to PGA applications when the DNP is too large. Therefore, what is needed is an interconnection, which is relatively flexible and capable of accommodating the thermal mismatch over an expected temperature range that can closely match the electrical performance and density of a BGA or CGA array.
One solution is to use an LGA connector. An array of interconnection elements, known as an interposer, is placed between two arrays to be connected, and provides the electrical connection between the contact pins or pads. Since the individual contact members of an interposer can be made resilient, they can accommodate a CTE (coefficient of thermal expansion) mismatch between the module and system board.
An LGA package is an integrated circuit package having a plurality of the integrated circuit and a printed circuit board. An LGA can be mounted to a printed circuit board with connectors, which have been developed to maintain a solderless connection between an integrated circuit package and a printed circuit board. As the number of lands is increased, the pitch between contacts decreases and manufacturing problems consequently increase.
For example, the manufacturing method of placing individual wires into tightly packed through-holes requires tremendous technological developments. Another example is a metallized polymer interconnect (MPI) connector. The MPI connector includes a siloxane core with conductive fillers that is positioned between the LGA module and the substrate. However, extreme stress relaxation rates are needed in order to achieve a desired level of durability.